1. Field of the Invention
The present invention relates to the field of the application of a voltage to an electrostatic chuck, and more particularly to the application of a voltage to an electrostatic chuck for easy removal of a workpiece attracted to the electrostatic chuck.
2. Description of the Relevant Art
Easy removal of a workpiece electrostatically attracted to an electrostatic chuck may be achieved by temporary reversal of the polarity of a voltage applied to the electrodes of the electrostatic chuck. Such a process of removing a workpiece from an electrostatic chuck is known from Japanese Patent Publication No. 47-39392, for example.
However, when the voltage is applied in the polarity opposite to the polarity of the voltage applied to attract the workpiece, for the removal of the workpiece from the electrostatic chuck, it takes a relatively long period of time (several tens of seconds or more) until the remaining force to attract the workpiece to the chuck is eliminated or reduced for easy removal of the workpiece. As a result, the efficiency of workpiece removal is low.